4 * Copyright (C) 1991-1998, Thomas G. Lane.
5 * This file is part of the Independent JPEG Group's software.
6 * For conditions of distribution and use, see the accompanying README file.
8 * This file defines the application interface for the JPEG library.
9 * Most applications using the library need only include this file,
10 * and perhaps jerror.h if they want to know the exact error codes.
20 /* HJH modification: protect compiler options for structure alignment and enum
21 * size if the compiler is Borland C++ */
23 #pragma option push -b
24 #pragma option push -a4
28 * First we include the configuration files that record how this
29 * installation of the JPEG library is set up. jconfig.h can be
30 * generated automatically for many systems. jmorecfg.h contains
31 * manual configuration options that most people need not worry about.
34 #ifndef JCONFIG_INCLUDED /* in case jinclude.h already did */
35 #include "jconfig.h" /* widely used configuration options */
37 #include "jmorecfg.h" /* seldom changed options */
40 /* Version ID for the JPEG library.
41 * Might be useful for tests like "#if JPEG_LIB_VERSION >= 60".
44 #define JPEG_LIB_VERSION 62 /* Version 6b */
47 /* Various constants determining the sizes of things.
48 * All of these are specified by the JPEG standard, so don't change them
49 * if you want to be compatible.
52 #define DCTSIZE 8 /* The basic DCT block is 8x8 samples */
53 #define DCTSIZE2 64 /* DCTSIZE squared; # of elements in a block */
54 #define NUM_QUANT_TBLS 4 /* Quantization tables are numbered 0..3 */
55 #define NUM_HUFF_TBLS 4 /* Huffman tables are numbered 0..3 */
56 #define NUM_ARITH_TBLS 16 /* Arith-coding tables are numbered 0..15 */
57 #define MAX_COMPS_IN_SCAN 4 /* JPEG limit on # of components in one scan */
58 #define MAX_SAMP_FACTOR 4 /* JPEG limit on sampling factors */
59 /* Unfortunately, some bozo at Adobe saw no reason to be bound by the standard;
60 * the PostScript DCT filter can emit files with many more than 10 blocks/MCU.
61 * If you happen to run across such a file, you can up D_MAX_BLOCKS_IN_MCU
62 * to handle it. We even let you do this from the jconfig.h file. However,
63 * we strongly discourage changing C_MAX_BLOCKS_IN_MCU; just because Adobe
64 * sometimes emits noncompliant files doesn't mean you should too.
66 #define C_MAX_BLOCKS_IN_MCU 10 /* compressor's limit on blocks per MCU */
67 #ifndef D_MAX_BLOCKS_IN_MCU
68 #define D_MAX_BLOCKS_IN_MCU 10 /* decompressor's limit on blocks per MCU */
72 /* Data structures for images (arrays of samples and of DCT coefficients).
73 * On 80x86 machines, the image arrays are too big for near pointers,
74 * but the pointer arrays can fit in near memory.
77 typedef JSAMPLE FAR *JSAMPROW; /* ptr to one image row of pixel samples. */
78 typedef JSAMPROW *JSAMPARRAY; /* ptr to some rows (a 2-D sample array) */
79 typedef JSAMPARRAY *JSAMPIMAGE; /* a 3-D sample array: top index is color */
81 typedef JCOEF JBLOCK[DCTSIZE2]; /* one block of coefficients */
82 typedef JBLOCK FAR *JBLOCKROW; /* pointer to one row of coefficient blocks */
83 typedef JBLOCKROW *JBLOCKARRAY; /* a 2-D array of coefficient blocks */
84 typedef JBLOCKARRAY *JBLOCKIMAGE; /* a 3-D array of coefficient blocks */
86 typedef JCOEF FAR *JCOEFPTR; /* useful in a couple of places */
89 /* Types for JPEG compression parameters and working tables. */
92 /* DCT coefficient quantization tables. */
95 /* This array gives the coefficient quantizers in natural array order
96 * (not the zigzag order in which they are stored in a JPEG DQT marker).
97 * CAUTION: IJG versions prior to v6a kept this array in zigzag order.
99 UINT16 quantval[DCTSIZE2]; /* quantization step for each coefficient */
100 /* This field is used only during compression. It's initialized FALSE when
101 * the table is created, and set TRUE when it's been output to the file.
102 * You could suppress output of a table by setting this to TRUE.
103 * (See jpeg_suppress_tables for an example.)
105 boolean sent_table; /* TRUE when table has been output */
109 /* Huffman coding tables. */
112 /* These two fields directly represent the contents of a JPEG DHT marker */
113 UINT8 bits[17]; /* bits[k] = # of symbols with codes of */
114 /* length k bits; bits[0] is unused */
115 UINT8 huffval[256]; /* The symbols, in order of incr code length */
116 /* This field is used only during compression. It's initialized FALSE when
117 * the table is created, and set TRUE when it's been output to the file.
118 * You could suppress output of a table by setting this to TRUE.
119 * (See jpeg_suppress_tables for an example.)
121 boolean sent_table; /* TRUE when table has been output */
125 /* Basic info about one component (color channel). */
128 /* These values are fixed over the whole image. */
129 /* For compression, they must be supplied by parameter setup; */
130 /* for decompression, they are read from the SOF marker. */
131 int component_id; /* identifier for this component (0..255) */
132 int component_index; /* its index in SOF or cinfo->comp_info[] */
133 int h_samp_factor; /* horizontal sampling factor (1..4) */
134 int v_samp_factor; /* vertical sampling factor (1..4) */
135 int quant_tbl_no; /* quantization table selector (0..3) */
136 /* These values may vary between scans. */
137 /* For compression, they must be supplied by parameter setup; */
138 /* for decompression, they are read from the SOS marker. */
139 /* The decompressor output side may not use these variables. */
140 int dc_tbl_no; /* DC entropy table selector (0..3) */
141 int ac_tbl_no; /* AC entropy table selector (0..3) */
143 /* Remaining fields should be treated as private by applications. */
145 /* These values are computed during compression or decompression startup: */
146 /* Component's size in DCT blocks.
147 * Any dummy blocks added to complete an MCU are not counted; therefore
148 * these values do not depend on whether a scan is interleaved or not.
150 JDIMENSION width_in_blocks;
151 JDIMENSION height_in_blocks;
152 /* Size of a DCT block in samples. Always DCTSIZE for compression.
153 * For decompression this is the size of the output from one DCT block,
154 * reflecting any scaling we choose to apply during the IDCT step.
155 * Values of 1,2,4,8 are likely to be supported. Note that different
156 * components may receive different IDCT scalings.
159 /* The downsampled dimensions are the component's actual, unpadded number
160 * of samples at the main buffer (preprocessing/compression interface), thus
161 * downsampled_width = ceil(image_width * Hi/Hmax)
162 * and similarly for height. For decompression, IDCT scaling is included, so
163 * downsampled_width = ceil(image_width * Hi/Hmax * DCT_scaled_size/DCTSIZE)
165 JDIMENSION downsampled_width; /* actual width in samples */
166 JDIMENSION downsampled_height; /* actual height in samples */
167 /* This flag is used only for decompression. In cases where some of the
168 * components will be ignored (eg grayscale output from YCbCr image),
169 * we can skip most computations for the unused components.
171 boolean component_needed; /* do we need the value of this component? */
173 /* These values are computed before starting a scan of the component. */
174 /* The decompressor output side may not use these variables. */
175 int MCU_width; /* number of blocks per MCU, horizontally */
176 int MCU_height; /* number of blocks per MCU, vertically */
177 int MCU_blocks; /* MCU_width * MCU_height */
178 int MCU_sample_width; /* MCU width in samples, MCU_width*DCT_scaled_size */
179 int last_col_width; /* # of non-dummy blocks across in last MCU */
180 int last_row_height; /* # of non-dummy blocks down in last MCU */
182 /* Saved quantization table for component; NULL if none yet saved.
183 * See jdinput.c comments about the need for this information.
184 * This field is currently used only for decompression.
186 JQUANT_TBL * quant_table;
188 /* Private per-component storage for DCT or IDCT subsystem. */
190 } jpeg_component_info;
193 /* The script for encoding a multiple-scan file is an array of these: */
196 int comps_in_scan; /* number of components encoded in this scan */
197 int component_index[MAX_COMPS_IN_SCAN]; /* their SOF/comp_info[] indexes */
198 int Ss, Se; /* progressive JPEG spectral selection parms */
199 int Ah, Al; /* progressive JPEG successive approx. parms */
202 /* The decompressor can save APPn and COM markers in a list of these: */
204 typedef struct jpeg_marker_struct FAR * jpeg_saved_marker_ptr;
206 struct jpeg_marker_struct {
207 jpeg_saved_marker_ptr next; /* next in list, or NULL */
208 UINT8 marker; /* marker code: JPEG_COM, or JPEG_APP0+n */
209 unsigned int original_length; /* # bytes of data in the file */
210 unsigned int data_length; /* # bytes of data saved at data[] */
211 JOCTET FAR * data; /* the data contained in the marker */
212 /* the marker length word is not counted in data_length or original_length */
215 /* Known color spaces. */
218 JCS_UNKNOWN, /* error/unspecified */
219 JCS_GRAYSCALE, /* monochrome */
220 JCS_RGB, /* red/green/blue */
221 JCS_YCbCr, /* Y/Cb/Cr (also known as YUV) */
222 JCS_CMYK, /* C/M/Y/K */
223 JCS_YCCK /* Y/Cb/Cr/K */
226 /* DCT/IDCT algorithm options. */
229 JDCT_ISLOW, /* slow but accurate integer algorithm */
230 JDCT_IFAST, /* faster, less accurate integer method */
231 JDCT_FLOAT /* floating-point: accurate, fast on fast HW */
234 #ifndef JDCT_DEFAULT /* may be overridden in jconfig.h */
235 #define JDCT_DEFAULT JDCT_ISLOW
237 #ifndef JDCT_FASTEST /* may be overridden in jconfig.h */
238 #define JDCT_FASTEST JDCT_IFAST
241 /* Dithering options for decompression. */
244 JDITHER_NONE, /* no dithering */
245 JDITHER_ORDERED, /* simple ordered dither */
246 JDITHER_FS /* Floyd-Steinberg error diffusion dither */
250 /* Common fields between JPEG compression and decompression master structs. */
252 #define jpeg_common_fields \
253 struct jpeg_error_mgr * err; /* Error handler module */\
254 struct jpeg_memory_mgr * mem; /* Memory manager module */\
255 struct jpeg_progress_mgr * progress; /* Progress monitor, or NULL if none */\
256 void * client_data; /* Available for use by application */\
257 boolean is_decompressor; /* So common code can tell which is which */\
258 int global_state /* For checking call sequence validity */
260 /* Routines that are to be used by both halves of the library are declared
261 * to receive a pointer to this structure. There are no actual instances of
262 * jpeg_common_struct, only of jpeg_compress_struct and jpeg_decompress_struct.
264 struct jpeg_common_struct {
265 jpeg_common_fields; /* Fields common to both master struct types */
266 /* Additional fields follow in an actual jpeg_compress_struct or
267 * jpeg_decompress_struct. All three structs must agree on these
268 * initial fields! (This would be a lot cleaner in C++.)
272 typedef struct jpeg_common_struct * j_common_ptr;
273 typedef struct jpeg_compress_struct * j_compress_ptr;
274 typedef struct jpeg_decompress_struct * j_decompress_ptr;
277 /* Master record for a compression instance */
279 struct jpeg_compress_struct {
280 jpeg_common_fields; /* Fields shared with jpeg_decompress_struct */
282 /* Destination for compressed data */
283 struct jpeg_destination_mgr * dest;
285 /* Description of source image --- these fields must be filled in by
286 * outer application before starting compression. in_color_space must
287 * be correct before you can even call jpeg_set_defaults().
290 JDIMENSION image_width; /* input image width */
291 JDIMENSION image_height; /* input image height */
292 int input_components; /* # of color components in input image */
293 J_COLOR_SPACE in_color_space; /* colorspace of input image */
295 double input_gamma; /* image gamma of input image */
297 /* Compression parameters --- these fields must be set before calling
298 * jpeg_start_compress(). We recommend calling jpeg_set_defaults() to
299 * initialize everything to reasonable defaults, then changing anything
300 * the application specifically wants to change. That way you won't get
301 * burnt when new parameters are added. Also note that there are several
302 * helper routines to simplify changing parameters.
305 int data_precision; /* bits of precision in image data */
307 int num_components; /* # of color components in JPEG image */
308 J_COLOR_SPACE jpeg_color_space; /* colorspace of JPEG image */
310 jpeg_component_info * comp_info;
311 /* comp_info[i] describes component that appears i'th in SOF */
313 JQUANT_TBL * quant_tbl_ptrs[NUM_QUANT_TBLS];
314 /* ptrs to coefficient quantization tables, or NULL if not defined */
316 JHUFF_TBL * dc_huff_tbl_ptrs[NUM_HUFF_TBLS];
317 JHUFF_TBL * ac_huff_tbl_ptrs[NUM_HUFF_TBLS];
318 /* ptrs to Huffman coding tables, or NULL if not defined */
320 UINT8 arith_dc_L[NUM_ARITH_TBLS]; /* L values for DC arith-coding tables */
321 UINT8 arith_dc_U[NUM_ARITH_TBLS]; /* U values for DC arith-coding tables */
322 UINT8 arith_ac_K[NUM_ARITH_TBLS]; /* Kx values for AC arith-coding tables */
324 int num_scans; /* # of entries in scan_info array */
325 const jpeg_scan_info * scan_info; /* script for multi-scan file, or NULL */
326 /* The default value of scan_info is NULL, which causes a single-scan
327 * sequential JPEG file to be emitted. To create a multi-scan file,
328 * set num_scans and scan_info to point to an array of scan definitions.
331 boolean raw_data_in; /* TRUE=caller supplies downsampled data */
332 boolean arith_code; /* TRUE=arithmetic coding, FALSE=Huffman */
333 boolean optimize_coding; /* TRUE=optimize entropy encoding parms */
334 boolean CCIR601_sampling; /* TRUE=first samples are cosited */
335 int smoothing_factor; /* 1..100, or 0 for no input smoothing */
336 J_DCT_METHOD dct_method; /* DCT algorithm selector */
338 /* The restart interval can be specified in absolute MCUs by setting
339 * restart_interval, or in MCU rows by setting restart_in_rows
340 * (in which case the correct restart_interval will be figured
343 unsigned int restart_interval; /* MCUs per restart, or 0 for no restart */
344 int restart_in_rows; /* if > 0, MCU rows per restart interval */
346 /* Parameters controlling emission of special markers. */
348 boolean write_JFIF_header; /* should a JFIF marker be written? */
349 UINT8 JFIF_major_version; /* What to write for the JFIF version number */
350 UINT8 JFIF_minor_version;
351 /* These three values are not used by the JPEG code, merely copied */
352 /* into the JFIF APP0 marker. density_unit can be 0 for unknown, */
353 /* 1 for dots/inch, or 2 for dots/cm. Note that the pixel aspect */
354 /* ratio is defined by X_density/Y_density even when density_unit=0. */
355 UINT8 density_unit; /* JFIF code for pixel size units */
356 UINT16 X_density; /* Horizontal pixel density */
357 UINT16 Y_density; /* Vertical pixel density */
358 boolean write_Adobe_marker; /* should an Adobe marker be written? */
360 /* State variable: index of next scanline to be written to
361 * jpeg_write_scanlines(). Application may use this to control its
362 * processing loop, e.g., "while (next_scanline < image_height)".
365 JDIMENSION next_scanline; /* 0 .. image_height-1 */
367 /* Remaining fields are known throughout compressor, but generally
368 * should not be touched by a surrounding application.
372 * These fields are computed during compression startup
374 boolean progressive_mode; /* TRUE if scan script uses progressive mode */
375 int max_h_samp_factor; /* largest h_samp_factor */
376 int max_v_samp_factor; /* largest v_samp_factor */
378 JDIMENSION total_iMCU_rows; /* # of iMCU rows to be input to coef ctlr */
379 /* The coefficient controller receives data in units of MCU rows as defined
380 * for fully interleaved scans (whether the JPEG file is interleaved or not).
381 * There are v_samp_factor * DCTSIZE sample rows of each component in an
382 * "iMCU" (interleaved MCU) row.
386 * These fields are valid during any one scan.
387 * They describe the components and MCUs actually appearing in the scan.
389 int comps_in_scan; /* # of JPEG components in this scan */
390 jpeg_component_info * cur_comp_info[MAX_COMPS_IN_SCAN];
391 /* *cur_comp_info[i] describes component that appears i'th in SOS */
393 JDIMENSION MCUs_per_row; /* # of MCUs across the image */
394 JDIMENSION MCU_rows_in_scan; /* # of MCU rows in the image */
396 int blocks_in_MCU; /* # of DCT blocks per MCU */
397 int MCU_membership[C_MAX_BLOCKS_IN_MCU];
398 /* MCU_membership[i] is index in cur_comp_info of component owning */
399 /* i'th block in an MCU */
401 int Ss, Se, Ah, Al; /* progressive JPEG parameters for scan */
404 * Links to compression subobjects (methods and private variables of modules)
406 struct jpeg_comp_master * master;
407 struct jpeg_c_main_controller * main;
408 struct jpeg_c_prep_controller * prep;
409 struct jpeg_c_coef_controller * coef;
410 struct jpeg_marker_writer * marker;
411 struct jpeg_color_converter * cconvert;
412 struct jpeg_downsampler * downsample;
413 struct jpeg_forward_dct * fdct;
414 struct jpeg_entropy_encoder * entropy;
415 jpeg_scan_info * script_space; /* workspace for jpeg_simple_progression */
416 int script_space_size;
420 /* Master record for a decompression instance */
422 struct jpeg_decompress_struct {
423 jpeg_common_fields; /* Fields shared with jpeg_compress_struct */
425 /* Source of compressed data */
426 struct jpeg_source_mgr * src;
428 /* Basic description of image --- filled in by jpeg_read_header(). */
429 /* Application may inspect these values to decide how to process image. */
431 JDIMENSION image_width; /* nominal image width (from SOF marker) */
432 JDIMENSION image_height; /* nominal image height */
433 int num_components; /* # of color components in JPEG image */
434 J_COLOR_SPACE jpeg_color_space; /* colorspace of JPEG image */
436 /* Decompression processing parameters --- these fields must be set before
437 * calling jpeg_start_decompress(). Note that jpeg_read_header() initializes
438 * them to default values.
441 J_COLOR_SPACE out_color_space; /* colorspace for output */
443 unsigned int scale_num, scale_denom; /* fraction by which to scale image */
445 double output_gamma; /* image gamma wanted in output */
447 boolean buffered_image; /* TRUE=multiple output passes */
448 boolean raw_data_out; /* TRUE=downsampled data wanted */
450 J_DCT_METHOD dct_method; /* IDCT algorithm selector */
451 boolean do_fancy_upsampling; /* TRUE=apply fancy upsampling */
452 boolean do_block_smoothing; /* TRUE=apply interblock smoothing */
454 boolean quantize_colors; /* TRUE=colormapped output wanted */
455 /* the following are ignored if not quantize_colors: */
456 J_DITHER_MODE dither_mode; /* type of color dithering to use */
457 boolean two_pass_quantize; /* TRUE=use two-pass color quantization */
458 int desired_number_of_colors; /* max # colors to use in created colormap */
459 /* these are significant only in buffered-image mode: */
460 boolean enable_1pass_quant; /* enable future use of 1-pass quantizer */
461 boolean enable_external_quant;/* enable future use of external colormap */
462 boolean enable_2pass_quant; /* enable future use of 2-pass quantizer */
464 /* Description of actual output image that will be returned to application.
465 * These fields are computed by jpeg_start_decompress().
466 * You can also use jpeg_calc_output_dimensions() to determine these values
467 * in advance of calling jpeg_start_decompress().
470 JDIMENSION output_width; /* scaled image width */
471 JDIMENSION output_height; /* scaled image height */
472 int out_color_components; /* # of color components in out_color_space */
473 int output_components; /* # of color components returned */
474 /* output_components is 1 (a colormap index) when quantizing colors;
475 * otherwise it equals out_color_components.
477 int rec_outbuf_height; /* min recommended height of scanline buffer */
478 /* If the buffer passed to jpeg_read_scanlines() is less than this many rows
479 * high, space and time will be wasted due to unnecessary data copying.
480 * Usually rec_outbuf_height will be 1 or 2, at most 4.
483 /* When quantizing colors, the output colormap is described by these fields.
484 * The application can supply a colormap by setting colormap non-NULL before
485 * calling jpeg_start_decompress; otherwise a colormap is created during
486 * jpeg_start_decompress or jpeg_start_output.
487 * The map has out_color_components rows and actual_number_of_colors columns.
489 int actual_number_of_colors; /* number of entries in use */
490 JSAMPARRAY colormap; /* The color map as a 2-D pixel array */
492 /* State variables: these variables indicate the progress of decompression.
493 * The application may examine these but must not modify them.
496 /* Row index of next scanline to be read from jpeg_read_scanlines().
497 * Application may use this to control its processing loop, e.g.,
498 * "while (output_scanline < output_height)".
500 JDIMENSION output_scanline; /* 0 .. output_height-1 */
502 /* Current input scan number and number of iMCU rows completed in scan.
503 * These indicate the progress of the decompressor input side.
505 int input_scan_number; /* Number of SOS markers seen so far */
506 JDIMENSION input_iMCU_row; /* Number of iMCU rows completed */
508 /* The "output scan number" is the notional scan being displayed by the
509 * output side. The decompressor will not allow output scan/row number
510 * to get ahead of input scan/row, but it can fall arbitrarily far behind.
512 int output_scan_number; /* Nominal scan number being displayed */
513 JDIMENSION output_iMCU_row; /* Number of iMCU rows read */
515 /* Current progression status. coef_bits[c][i] indicates the precision
516 * with which component c's DCT coefficient i (in zigzag order) is known.
517 * It is -1 when no data has yet been received, otherwise it is the point
518 * transform (shift) value for the most recent scan of the coefficient
519 * (thus, 0 at completion of the progression).
520 * This pointer is NULL when reading a non-progressive file.
522 int (*coef_bits)[DCTSIZE2]; /* -1 or current Al value for each coef */
524 /* Internal JPEG parameters --- the application usually need not look at
525 * these fields. Note that the decompressor output side may not use
526 * any parameters that can change between scans.
529 /* Quantization and Huffman tables are carried forward across input
530 * datastreams when processing abbreviated JPEG datastreams.
533 JQUANT_TBL * quant_tbl_ptrs[NUM_QUANT_TBLS];
534 /* ptrs to coefficient quantization tables, or NULL if not defined */
536 JHUFF_TBL * dc_huff_tbl_ptrs[NUM_HUFF_TBLS];
537 JHUFF_TBL * ac_huff_tbl_ptrs[NUM_HUFF_TBLS];
538 /* ptrs to Huffman coding tables, or NULL if not defined */
540 /* These parameters are never carried across datastreams, since they
541 * are given in SOF/SOS markers or defined to be reset by SOI.
544 int data_precision; /* bits of precision in image data */
546 jpeg_component_info * comp_info;
547 /* comp_info[i] describes component that appears i'th in SOF */
549 boolean progressive_mode; /* TRUE if SOFn specifies progressive mode */
550 boolean arith_code; /* TRUE=arithmetic coding, FALSE=Huffman */
552 UINT8 arith_dc_L[NUM_ARITH_TBLS]; /* L values for DC arith-coding tables */
553 UINT8 arith_dc_U[NUM_ARITH_TBLS]; /* U values for DC arith-coding tables */
554 UINT8 arith_ac_K[NUM_ARITH_TBLS]; /* Kx values for AC arith-coding tables */
556 unsigned int restart_interval; /* MCUs per restart interval, or 0 for no restart */
558 /* These fields record data obtained from optional markers recognized by
561 boolean saw_JFIF_marker; /* TRUE iff a JFIF APP0 marker was found */
562 /* Data copied from JFIF marker; only valid if saw_JFIF_marker is TRUE: */
563 UINT8 JFIF_major_version; /* JFIF version number */
564 UINT8 JFIF_minor_version;
565 UINT8 density_unit; /* JFIF code for pixel size units */
566 UINT16 X_density; /* Horizontal pixel density */
567 UINT16 Y_density; /* Vertical pixel density */
568 boolean saw_Adobe_marker; /* TRUE iff an Adobe APP14 marker was found */
569 UINT8 Adobe_transform; /* Color transform code from Adobe marker */
571 boolean CCIR601_sampling; /* TRUE=first samples are cosited */
573 /* Aside from the specific data retained from APPn markers known to the
574 * library, the uninterpreted contents of any or all APPn and COM markers
575 * can be saved in a list for examination by the application.
577 jpeg_saved_marker_ptr marker_list; /* Head of list of saved markers */
579 /* Remaining fields are known throughout decompressor, but generally
580 * should not be touched by a surrounding application.
584 * These fields are computed during decompression startup
586 int max_h_samp_factor; /* largest h_samp_factor */
587 int max_v_samp_factor; /* largest v_samp_factor */
589 int min_DCT_scaled_size; /* smallest DCT_scaled_size of any component */
591 JDIMENSION total_iMCU_rows; /* # of iMCU rows in image */
592 /* The coefficient controller's input and output progress is measured in
593 * units of "iMCU" (interleaved MCU) rows. These are the same as MCU rows
594 * in fully interleaved JPEG scans, but are used whether the scan is
595 * interleaved or not. We define an iMCU row as v_samp_factor DCT block
596 * rows of each component. Therefore, the IDCT output contains
597 * v_samp_factor*DCT_scaled_size sample rows of a component per iMCU row.
600 JSAMPLE * sample_range_limit; /* table for fast range-limiting */
603 * These fields are valid during any one scan.
604 * They describe the components and MCUs actually appearing in the scan.
605 * Note that the decompressor output side must not use these fields.
607 int comps_in_scan; /* # of JPEG components in this scan */
608 jpeg_component_info * cur_comp_info[MAX_COMPS_IN_SCAN];
609 /* *cur_comp_info[i] describes component that appears i'th in SOS */
611 JDIMENSION MCUs_per_row; /* # of MCUs across the image */
612 JDIMENSION MCU_rows_in_scan; /* # of MCU rows in the image */
614 int blocks_in_MCU; /* # of DCT blocks per MCU */
615 int MCU_membership[D_MAX_BLOCKS_IN_MCU];
616 /* MCU_membership[i] is index in cur_comp_info of component owning */
617 /* i'th block in an MCU */
619 int Ss, Se, Ah, Al; /* progressive JPEG parameters for scan */
621 /* This field is shared between entropy decoder and marker parser.
622 * It is either zero or the code of a JPEG marker that has been
623 * read from the data source, but has not yet been processed.
628 * Links to decompression subobjects (methods, private variables of modules)
630 struct jpeg_decomp_master * master;
631 struct jpeg_d_main_controller * main;
632 struct jpeg_d_coef_controller * coef;
633 struct jpeg_d_post_controller * post;
634 struct jpeg_input_controller * inputctl;
635 struct jpeg_marker_reader * marker;
636 struct jpeg_entropy_decoder * entropy;
637 struct jpeg_inverse_dct * idct;
638 struct jpeg_upsampler * upsample;
639 struct jpeg_color_deconverter * cconvert;
640 struct jpeg_color_quantizer * cquantize;
644 /* "Object" declarations for JPEG modules that may be supplied or called
645 * directly by the surrounding application.
646 * As with all objects in the JPEG library, these structs only define the
647 * publicly visible methods and state variables of a module. Additional
648 * private fields may exist after the public ones.
652 /* Error handler object */
654 struct jpeg_error_mgr {
655 /* Error exit handler: does not return to caller */
656 JMETHOD(void, error_exit, (j_common_ptr cinfo));
657 /* Conditionally emit a trace or warning message */
658 JMETHOD(void, emit_message, (j_common_ptr cinfo, int msg_level));
659 /* Routine that actually outputs a trace or error message */
660 JMETHOD(void, output_message, (j_common_ptr cinfo));
661 /* Format a message string for the most recent JPEG error or message */
662 JMETHOD(void, format_message, (j_common_ptr cinfo, char * buffer));
663 #define JMSG_LENGTH_MAX 200 /* recommended size of format_message buffer */
664 /* Reset error state variables at start of a new image */
665 JMETHOD(void, reset_error_mgr, (j_common_ptr cinfo));
667 /* The message ID code and any parameters are saved here.
668 * A message can have one string parameter or up to 8 int parameters.
671 #define JMSG_STR_PARM_MAX 80
674 char s[JMSG_STR_PARM_MAX];
677 /* Standard state variables for error facility */
679 int trace_level; /* max msg_level that will be displayed */
681 /* For recoverable corrupt-data errors, we emit a warning message,
682 * but keep going unless emit_message chooses to abort. emit_message
683 * should count warnings in num_warnings. The surrounding application
684 * can check for bad data by seeing if num_warnings is nonzero at the
687 long num_warnings; /* number of corrupt-data warnings */
689 /* These fields point to the table(s) of error message strings.
690 * An application can change the table pointer to switch to a different
691 * message list (typically, to change the language in which errors are
692 * reported). Some applications may wish to add additional error codes
693 * that will be handled by the JPEG library error mechanism; the second
694 * table pointer is used for this purpose.
696 * First table includes all errors generated by JPEG library itself.
697 * Error code 0 is reserved for a "no such error string" message.
699 const char * const * jpeg_message_table; /* Library errors */
700 int last_jpeg_message; /* Table contains strings 0..last_jpeg_message */
701 /* Second table can be added by application (see cjpeg/djpeg for example).
702 * It contains strings numbered first_addon_message..last_addon_message.
704 const char * const * addon_message_table; /* Non-library errors */
705 int first_addon_message; /* code for first string in addon table */
706 int last_addon_message; /* code for last string in addon table */
710 /* Progress monitor object */
712 struct jpeg_progress_mgr {
713 JMETHOD(void, progress_monitor, (j_common_ptr cinfo));
715 long pass_counter; /* work units completed in this pass */
716 long pass_limit; /* total number of work units in this pass */
717 int completed_passes; /* passes completed so far */
718 int total_passes; /* total number of passes expected */
722 /* Data destination object for compression */
724 struct jpeg_destination_mgr {
725 JOCTET * next_output_byte; /* => next byte to write in buffer */
726 size_t free_in_buffer; /* # of byte spaces remaining in buffer */
728 JMETHOD(void, init_destination, (j_compress_ptr cinfo));
729 JMETHOD(boolean, empty_output_buffer, (j_compress_ptr cinfo));
730 JMETHOD(void, term_destination, (j_compress_ptr cinfo));
734 /* Data source object for decompression */
736 struct jpeg_source_mgr {
737 const JOCTET * next_input_byte; /* => next byte to read from buffer */
738 size_t bytes_in_buffer; /* # of bytes remaining in buffer */
740 JMETHOD(void, init_source, (j_decompress_ptr cinfo));
741 JMETHOD(boolean, fill_input_buffer, (j_decompress_ptr cinfo));
742 JMETHOD(void, skip_input_data, (j_decompress_ptr cinfo, long num_bytes));
743 JMETHOD(boolean, resync_to_restart, (j_decompress_ptr cinfo, int desired));
744 JMETHOD(void, term_source, (j_decompress_ptr cinfo));
748 /* Memory manager object.
749 * Allocates "small" objects (a few K total), "large" objects (tens of K),
750 * and "really big" objects (virtual arrays with backing store if needed).
751 * The memory manager does not allow individual objects to be freed; rather,
752 * each created object is assigned to a pool, and whole pools can be freed
753 * at once. This is faster and more convenient than remembering exactly what
754 * to free, especially where malloc()/free() are not too speedy.
755 * NB: alloc routines never return NULL. They exit to error_exit if not
759 #define JPOOL_PERMANENT 0 /* lasts until master record is destroyed */
760 #define JPOOL_IMAGE 1 /* lasts until done with image/datastream */
761 #define JPOOL_NUMPOOLS 2
763 typedef struct jvirt_sarray_control * jvirt_sarray_ptr;
764 typedef struct jvirt_barray_control * jvirt_barray_ptr;
767 struct jpeg_memory_mgr {
768 /* Method pointers */
769 JMETHOD(void *, alloc_small, (j_common_ptr cinfo, int pool_id,
770 size_t sizeofobject));
771 JMETHOD(void FAR *, alloc_large, (j_common_ptr cinfo, int pool_id,
772 size_t sizeofobject));
773 JMETHOD(JSAMPARRAY, alloc_sarray, (j_common_ptr cinfo, int pool_id,
774 JDIMENSION samplesperrow,
775 JDIMENSION numrows));
776 JMETHOD(JBLOCKARRAY, alloc_barray, (j_common_ptr cinfo, int pool_id,
777 JDIMENSION blocksperrow,
778 JDIMENSION numrows));
779 JMETHOD(jvirt_sarray_ptr, request_virt_sarray, (j_common_ptr cinfo,
782 JDIMENSION samplesperrow,
784 JDIMENSION maxaccess));
785 JMETHOD(jvirt_barray_ptr, request_virt_barray, (j_common_ptr cinfo,
788 JDIMENSION blocksperrow,
790 JDIMENSION maxaccess));
791 JMETHOD(void, realize_virt_arrays, (j_common_ptr cinfo));
792 JMETHOD(JSAMPARRAY, access_virt_sarray, (j_common_ptr cinfo,
793 jvirt_sarray_ptr ptr,
794 JDIMENSION start_row,
797 JMETHOD(JBLOCKARRAY, access_virt_barray, (j_common_ptr cinfo,
798 jvirt_barray_ptr ptr,
799 JDIMENSION start_row,
802 JMETHOD(void, free_pool, (j_common_ptr cinfo, int pool_id));
803 JMETHOD(void, self_destruct, (j_common_ptr cinfo));
805 /* Limit on memory allocation for this JPEG object. (Note that this is
806 * merely advisory, not a guaranteed maximum; it only affects the space
807 * used for virtual-array buffers.) May be changed by outer application
808 * after creating the JPEG object.
810 long max_memory_to_use;
812 /* Maximum allocation request accepted by alloc_large. */
813 long max_alloc_chunk;
817 /* Routine signature for application-supplied marker processing methods.
818 * Need not pass marker code since it is stored in cinfo->unread_marker.
820 typedef JMETHOD(boolean, jpeg_marker_parser_method, (j_decompress_ptr cinfo));
823 /* Declarations for routines called by application.
824 * The JPP macro hides prototype parameters from compilers that can't cope.
825 * Note JPP requires double parentheses.
828 #ifdef HAVE_PROTOTYPES
829 #define JPP(arglist) arglist
831 #define JPP(arglist) ()
835 /* Short forms of external names for systems with brain-damaged linkers.
836 * We shorten external names to be unique in the first six letters, which
837 * is good enough for all known systems.
838 * (If your compiler itself needs names to be unique in less than 15
839 * characters, you are out of luck. Get a better compiler.)
842 #ifdef NEED_SHORT_EXTERNAL_NAMES
843 #define jpeg_std_error jStdError
844 #define jpeg_CreateCompress jCreaCompress
845 #define jpeg_CreateDecompress jCreaDecompress
846 #define jpeg_destroy_compress jDestCompress
847 #define jpeg_destroy_decompress jDestDecompress
848 #define jpeg_stdio_dest jStdDest
849 #define jpeg_stdio_src jStdSrc
850 #define jpeg_set_defaults jSetDefaults
851 #define jpeg_set_colorspace jSetColorspace
852 #define jpeg_default_colorspace jDefColorspace
853 #define jpeg_set_quality jSetQuality
854 #define jpeg_set_linear_quality jSetLQuality
855 #define jpeg_add_quant_table jAddQuantTable
856 #define jpeg_quality_scaling jQualityScaling
857 #define jpeg_simple_progression jSimProgress
858 #define jpeg_suppress_tables jSuppressTables
859 #define jpeg_alloc_quant_table jAlcQTable
860 #define jpeg_alloc_huff_table jAlcHTable
861 #define jpeg_start_compress jStrtCompress
862 #define jpeg_write_scanlines jWrtScanlines
863 #define jpeg_finish_compress jFinCompress
864 #define jpeg_write_raw_data jWrtRawData
865 #define jpeg_write_marker jWrtMarker
866 #define jpeg_write_m_header jWrtMHeader
867 #define jpeg_write_m_byte jWrtMByte
868 #define jpeg_write_tables jWrtTables
869 #define jpeg_read_header jReadHeader
870 #define jpeg_start_decompress jStrtDecompress
871 #define jpeg_read_scanlines jReadScanlines
872 #define jpeg_finish_decompress jFinDecompress
873 #define jpeg_read_raw_data jReadRawData
874 #define jpeg_has_multiple_scans jHasMultScn
875 #define jpeg_start_output jStrtOutput
876 #define jpeg_finish_output jFinOutput
877 #define jpeg_input_complete jInComplete
878 #define jpeg_new_colormap jNewCMap
879 #define jpeg_consume_input jConsumeInput
880 #define jpeg_calc_output_dimensions jCalcDimensions
881 #define jpeg_save_markers jSaveMarkers
882 #define jpeg_set_marker_processor jSetMarker
883 #define jpeg_read_coefficients jReadCoefs
884 #define jpeg_write_coefficients jWrtCoefs
885 #define jpeg_copy_critical_parameters jCopyCrit
886 #define jpeg_abort_compress jAbrtCompress
887 #define jpeg_abort_decompress jAbrtDecompress
888 #define jpeg_abort jAbort
889 #define jpeg_destroy jDestroy
890 #define jpeg_resync_to_restart jResyncRestart
891 #endif /* NEED_SHORT_EXTERNAL_NAMES */
894 /* Default error-management setup */
895 EXTERN(struct jpeg_error_mgr *) jpeg_std_error
896 JPP((struct jpeg_error_mgr * err));
898 /* Initialization of JPEG compression objects.
899 * jpeg_create_compress() and jpeg_create_decompress() are the exported
900 * names that applications should call. These expand to calls on
901 * jpeg_CreateCompress and jpeg_CreateDecompress with additional information
902 * passed for version mismatch checking.
903 * NB: you must set up the error-manager BEFORE calling jpeg_create_xxx.
905 #define jpeg_create_compress(cinfo) \
906 jpeg_CreateCompress((cinfo), JPEG_LIB_VERSION, \
907 (size_t) sizeof(struct jpeg_compress_struct))
908 #define jpeg_create_decompress(cinfo) \
909 jpeg_CreateDecompress((cinfo), JPEG_LIB_VERSION, \
910 (size_t) sizeof(struct jpeg_decompress_struct))
911 EXTERN(void) jpeg_CreateCompress JPP((j_compress_ptr cinfo,
912 int version, size_t structsize));
913 EXTERN(void) jpeg_CreateDecompress JPP((j_decompress_ptr cinfo,
914 int version, size_t structsize));
915 /* Destruction of JPEG compression objects */
916 EXTERN(void) jpeg_destroy_compress JPP((j_compress_ptr cinfo));
917 EXTERN(void) jpeg_destroy_decompress JPP((j_decompress_ptr cinfo));
919 /* Standard data source and destination managers: stdio streams. */
920 /* Caller is responsible for opening the file before and closing after. */
921 EXTERN(void) jpeg_stdio_dest JPP((j_compress_ptr cinfo, FILE * outfile));
922 EXTERN(void) jpeg_stdio_src JPP((j_decompress_ptr cinfo, FILE * infile));
924 /* Default parameter setup for compression */
925 EXTERN(void) jpeg_set_defaults JPP((j_compress_ptr cinfo));
926 /* Compression parameter setup aids */
927 EXTERN(void) jpeg_set_colorspace JPP((j_compress_ptr cinfo,
928 J_COLOR_SPACE colorspace));
929 EXTERN(void) jpeg_default_colorspace JPP((j_compress_ptr cinfo));
930 EXTERN(void) jpeg_set_quality JPP((j_compress_ptr cinfo, int quality,
931 boolean force_baseline));
932 EXTERN(void) jpeg_set_linear_quality JPP((j_compress_ptr cinfo,
934 boolean force_baseline));
935 EXTERN(void) jpeg_add_quant_table JPP((j_compress_ptr cinfo, int which_tbl,
936 const unsigned int *basic_table,
938 boolean force_baseline));
939 EXTERN(int) jpeg_quality_scaling JPP((int quality));
940 EXTERN(void) jpeg_simple_progression JPP((j_compress_ptr cinfo));
941 EXTERN(void) jpeg_suppress_tables JPP((j_compress_ptr cinfo,
943 EXTERN(JQUANT_TBL *) jpeg_alloc_quant_table JPP((j_common_ptr cinfo));
944 EXTERN(JHUFF_TBL *) jpeg_alloc_huff_table JPP((j_common_ptr cinfo));
946 /* Main entry points for compression */
947 EXTERN(void) jpeg_start_compress JPP((j_compress_ptr cinfo,
948 boolean write_all_tables));
949 EXTERN(JDIMENSION) jpeg_write_scanlines JPP((j_compress_ptr cinfo,
950 JSAMPARRAY scanlines,
951 JDIMENSION num_lines));
952 EXTERN(void) jpeg_finish_compress JPP((j_compress_ptr cinfo));
954 /* Replaces jpeg_write_scanlines when writing raw downsampled data. */
955 EXTERN(JDIMENSION) jpeg_write_raw_data JPP((j_compress_ptr cinfo,
957 JDIMENSION num_lines));
959 /* Write a special marker. See libjpeg.doc concerning safe usage. */
960 EXTERN(void) jpeg_write_marker
961 JPP((j_compress_ptr cinfo, int marker,
962 const JOCTET * dataptr, unsigned int datalen));
963 /* Same, but piecemeal. */
964 EXTERN(void) jpeg_write_m_header
965 JPP((j_compress_ptr cinfo, int marker, unsigned int datalen));
966 EXTERN(void) jpeg_write_m_byte
967 JPP((j_compress_ptr cinfo, int val));
969 /* Alternate compression function: just write an abbreviated table file */
970 EXTERN(void) jpeg_write_tables JPP((j_compress_ptr cinfo));
972 /* Decompression startup: read start of JPEG datastream to see what's there */
973 EXTERN(int) jpeg_read_header JPP((j_decompress_ptr cinfo,
974 boolean require_image));
975 /* Return value is one of: */
976 #define JPEG_SUSPENDED 0 /* Suspended due to lack of input data */
977 #define JPEG_HEADER_OK 1 /* Found valid image datastream */
978 #define JPEG_HEADER_TABLES_ONLY 2 /* Found valid table-specs-only datastream */
979 /* If you pass require_image = TRUE (normal case), you need not check for
980 * a TABLES_ONLY return code; an abbreviated file will cause an error exit.
981 * JPEG_SUSPENDED is only possible if you use a data source module that can
982 * give a suspension return (the stdio source module doesn't).
985 /* Main entry points for decompression */
986 EXTERN(boolean) jpeg_start_decompress JPP((j_decompress_ptr cinfo));
987 EXTERN(JDIMENSION) jpeg_read_scanlines JPP((j_decompress_ptr cinfo,
988 JSAMPARRAY scanlines,
989 JDIMENSION max_lines));
990 EXTERN(boolean) jpeg_finish_decompress JPP((j_decompress_ptr cinfo));
992 /* Replaces jpeg_read_scanlines when reading raw downsampled data. */
993 EXTERN(JDIMENSION) jpeg_read_raw_data JPP((j_decompress_ptr cinfo,
995 JDIMENSION max_lines));
997 /* Additional entry points for buffered-image mode. */
998 EXTERN(boolean) jpeg_has_multiple_scans JPP((j_decompress_ptr cinfo));
999 EXTERN(boolean) jpeg_start_output JPP((j_decompress_ptr cinfo,
1001 EXTERN(boolean) jpeg_finish_output JPP((j_decompress_ptr cinfo));
1002 EXTERN(boolean) jpeg_input_complete JPP((j_decompress_ptr cinfo));
1003 EXTERN(void) jpeg_new_colormap JPP((j_decompress_ptr cinfo));
1004 EXTERN(int) jpeg_consume_input JPP((j_decompress_ptr cinfo));
1005 /* Return value is one of: */
1006 /* #define JPEG_SUSPENDED 0 Suspended due to lack of input data */
1007 #define JPEG_REACHED_SOS 1 /* Reached start of new scan */
1008 #define JPEG_REACHED_EOI 2 /* Reached end of image */
1009 #define JPEG_ROW_COMPLETED 3 /* Completed one iMCU row */
1010 #define JPEG_SCAN_COMPLETED 4 /* Completed last iMCU row of a scan */
1012 /* Precalculate output dimensions for current decompression parameters. */
1013 EXTERN(void) jpeg_calc_output_dimensions JPP((j_decompress_ptr cinfo));
1015 /* Control saving of COM and APPn markers into marker_list. */
1016 EXTERN(void) jpeg_save_markers
1017 JPP((j_decompress_ptr cinfo, int marker_code,
1018 unsigned int length_limit));
1020 /* Install a special processing method for COM or APPn markers. */
1021 EXTERN(void) jpeg_set_marker_processor
1022 JPP((j_decompress_ptr cinfo, int marker_code,
1023 jpeg_marker_parser_method routine));
1025 /* Read or write raw DCT coefficients --- useful for lossless transcoding. */
1026 EXTERN(jvirt_barray_ptr *) jpeg_read_coefficients JPP((j_decompress_ptr cinfo));
1027 EXTERN(void) jpeg_write_coefficients JPP((j_compress_ptr cinfo,
1028 jvirt_barray_ptr * coef_arrays));
1029 EXTERN(void) jpeg_copy_critical_parameters JPP((j_decompress_ptr srcinfo,
1030 j_compress_ptr dstinfo));
1032 /* If you choose to abort compression or decompression before completing
1033 * jpeg_finish_(de)compress, then you need to clean up to release memory,
1034 * temporary files, etc. You can just call jpeg_destroy_(de)compress
1035 * if you're done with the JPEG object, but if you want to clean it up and
1036 * reuse it, call this:
1038 EXTERN(void) jpeg_abort_compress JPP((j_compress_ptr cinfo));
1039 EXTERN(void) jpeg_abort_decompress JPP((j_decompress_ptr cinfo));
1041 /* Generic versions of jpeg_abort and jpeg_destroy that work on either
1042 * flavor of JPEG object. These may be more convenient in some places.
1044 EXTERN(void) jpeg_abort JPP((j_common_ptr cinfo));
1045 EXTERN(void) jpeg_destroy JPP((j_common_ptr cinfo));
1047 /* Default restart-marker-resync procedure for use by data source modules */
1048 EXTERN(boolean) jpeg_resync_to_restart JPP((j_decompress_ptr cinfo,
1052 /* These marker codes are exported since applications and data source modules
1053 * are likely to want to use them.
1056 #define JPEG_RST0 0xD0 /* RST0 marker code */
1057 #define JPEG_EOI 0xD9 /* EOI marker code */
1058 #define JPEG_APP0 0xE0 /* APP0 marker code */
1059 #define JPEG_COM 0xFE /* COM marker code */
1062 /* If we have a brain-damaged compiler that emits warnings (or worse, errors)
1063 * for structure definitions that are never filled in, keep it quiet by
1064 * supplying dummy definitions for the various substructures.
1067 #ifdef INCOMPLETE_TYPES_BROKEN
1068 #ifndef JPEG_INTERNALS /* will be defined in jpegint.h */
1069 struct jvirt_sarray_control { long dummy; };
1070 struct jvirt_barray_control { long dummy; };
1071 struct jpeg_comp_master { long dummy; };
1072 struct jpeg_c_main_controller { long dummy; };
1073 struct jpeg_c_prep_controller { long dummy; };
1074 struct jpeg_c_coef_controller { long dummy; };
1075 struct jpeg_marker_writer { long dummy; };
1076 struct jpeg_color_converter { long dummy; };
1077 struct jpeg_downsampler { long dummy; };
1078 struct jpeg_forward_dct { long dummy; };
1079 struct jpeg_entropy_encoder { long dummy; };
1080 struct jpeg_decomp_master { long dummy; };
1081 struct jpeg_d_main_controller { long dummy; };
1082 struct jpeg_d_coef_controller { long dummy; };
1083 struct jpeg_d_post_controller { long dummy; };
1084 struct jpeg_input_controller { long dummy; };
1085 struct jpeg_marker_reader { long dummy; };
1086 struct jpeg_entropy_decoder { long dummy; };
1087 struct jpeg_inverse_dct { long dummy; };
1088 struct jpeg_upsampler { long dummy; };
1089 struct jpeg_color_deconverter { long dummy; };
1090 struct jpeg_color_quantizer { long dummy; };
1091 #endif /* JPEG_INTERNALS */
1092 #endif /* INCOMPLETE_TYPES_BROKEN */
1096 * The JPEG library modules define JPEG_INTERNALS before including this file.
1097 * The internal structure declarations are read only when that is true.
1098 * Applications using the library should not include jpegint.h, but may wish
1099 * to include jerror.h.
1102 #ifdef JPEG_INTERNALS
1103 #include "jpegint.h" /* fetch private declarations */
1104 #include "jerror.h" /* fetch error codes too */
1108 #pragma option pop /* pop -a switch */
1109 #pragma option pop /* pop -b */
1116 #endif /* JPEGLIB_H */
projects / opencv / blob